Grocery delivery service Instacart has raised a new round of $400 million led by Sequoia Capital. The money will help the on-demand grocer expand. Already, Instacart works with 135 retailers and operates in 35 markets around the country.

While the unicorn has made big progress this year, it also pissed off its workers. In September 2016, Instacart took away the ability to tip workers and replaced it with a service fee—a portion of which the company claims for itself. After a backlash, Instacart added the tipping back but kept the new service fee. The company’s battalion of food pickers and deliverers have also faced other tweaks to their pay in the last year. While workers are vital to Instacarts operations, the changes in pay structure stand to boost revenues. But Instacart still has much work to do if it wants to prove that its business model will work.